Cron Jobs [moved]

I did make a previous post on this but i thought id go back to square one on this and try basic stuff.

Say for example i want to do a cron job, i go into basic under cron and it asks "command to run" can someone please supply me with a example of how to backup a mysql database here and if its possible to backup more than 1 in the cron job.

I am also looking for a way of e-mail these backups to me then get them deleted off the server, but thats another story ! maybe thats not possible. if someone knows about that it will be a bonus. If not i will have to ftp them somehow..